176 HISTORICAL PALAEONTOLOGY. 



limestones which are found in the Coal-measures of the United 



States, in Ohio, Illinois, 

 Indiana, Missouri, &c. Mr. 

 Henry Brady, lastly, has 

 shown that we have in the 



Nummulina pristina of the 

 Fig. 115. Fumllna cylindnca. Carbon- ~ . . .. P 



iferous Limestone, Russia. Carboniferous Limestone of 



Namur a genuine Nummu- 



lite, precursor of the great important family of the Tertiary 

 Nummulites. 



The sub-kingdom of the Ccelenterates, so far as certainly 

 known, is represented only by Corals ; * but the remains of 

 these are so abundant in many of the limestones of the Car- 

 boniferous formation as to constitute a feature little or not at 

 all less conspicuous than that afforded by the Crinoids. As is 

 the case in the preceding period, the Corals belong, almost 

 exclusively, to the groups of the Rugosa and Tabulata; and 

 there is a general and striking resemblance and relationship 

 between the coral-fauna of the Devonian as a whole, and that 

 of the Carboniferous. Nevertheless, there is an equally decided 

 and striking amount of difference between these successive 

 faunas, due to the fact that the great majority of the Carbon- 

 iferous species are new ; whilst some of the most characteristic 

 Devonian genera have nearly or quite disappeared, and several 

 new genera now make their appearance for the first time. 

 Thus, the characteristic Devonian types Heliophyllum, Pachy- 

 phyllum, Chonophyllum, Acervularia, Spongophyllum, Smithia, 

 Endophyllum, and Cystiphyllum, have now disappeared ; and 

 the great masses of Favosites which are such a striking feature 

 in the Devonian limestones, are represented but by one or two 

 degenerate and puny successors. On the other hand, we meet 

 in the Carboniferous rocks not only with entirely new genera 

 such as Axophyllum, Lophophyllum, and Londsdaleia but we 

 have an enormous expansion of certain types which had just 

 begun to exist in the preceding period. This is especially 

 well seen in the case of the genus Lithostrotion (fig. 116, fc), 

 which more than any other may be considered as the predom- 

 inant Carboniferous group of Corals. All the species of 

 Lithostrotion are compound, consisting either of bundles of 



* A singular fossil has been described by Professor Martin Duncan 

 and Mr. Jenkins from the Carboniferous rocks under the name of Palao- 

 corvne, and has been referred to the Hydroid Zoophytes (Corynida). 

 Doubt, however, has been thrown by other observers on the correctness 

 of this reference. 



